Scientists Discover Exoplanet Less Than Twice the Mass of Earth

Snowblindeye writes with this excerpt from the European Southern Observatory: "Well-known exoplanet researcher Michel Mayor today announced the discovery of the lightest exoplanet found so far. The planet, 'e,' in the famous system Gliese 581, is only about twice the mass of Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist. Planet Gliese 581 e orbits its host star — located only 20.5 light-years away in the constellation Libra ('the Scales') — in just 3.15 days. 'With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet,' says co-author Xavier Bonfils from Grenoble Observatory. Being so close to its host star, the planet is not in the habitable zone. But another planet in this system appears to be. ... The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days. 'Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,' says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. '"d" could even be covered by a large and deep ocean — it is the first serious "water world" candidate,' continued Udry."

Comments

Astronomy

[Reorix]

I always hear about these sorts of discoveries, of new planets more and more similar to earth, but having almost no astronomy background, I have no idea how significant they are.

How much do we really know about these planets, and how much is guessing? How close are these planets, really, to earth?

Re:Astronomy

[olsmeister]

It's 20 (or so) light years from Earth. According to this article, we've probably already pissed off any inhabitants...

Re:Astronomy

[confused one]

The significance is that our methodology is improving. Only in the past decade or so have we been able to identify stars with possible planets. Only in the past year or two have we been able to directly image a planet (or separate it's image from the parent star). What we know of the planets is based on how close it's orbit is to the star, it's estimated mass, and in a few recent cases, based on limited spectroscopic information.

Now that Kepler's working, over the next 2-3 years we should have a flood of these reports. (keep in mind Kepler's only imaging a 10 x 10 degree patch of sky) In the next decade we will develop the means to directly image a nearby terrestrial sized planet.

All of the planets imaged so far are relatively close, on a galactic scale. A few 10's of light years. There's more than enough information out there to explain how far that is from a human perspective. Let's just say, that based on current technology, none of our great-grand children will get an up close look. (although I suppose we could do a fly by of something like the Gliese 581 system, with a probe, in the next 3-4 generations, if we tried hard enough.

Re:Astronomy

[jollyreaper]

It's 20 (or so) light years from Earth. According to this [theregister.co.uk] article, we've probably already pissed off any inhabitants...

We still have what, ten years left to invent an FTL drive and get there to preemptively apologize for reality television, right?

Re:Astronomy

[dragonbutt]

directly image a nearby terrestrial sized planet.

You must be using VERY large values of nearby

Re:Astronomy

[Anonymous Coward]

j = the speed of light = 670 616 629 mph
y = 20 light years = (20*365.242199*24)
x = 36000 mph, the speed I googled off some rocket going to pluto
(((j * y) / x) / 24) / 365.242199 = 372 564.794

My math is probably wrong here, but wouldn't it take 372,565 years to send a probe there under current achievable speeds?

Re:Astronomy

[Rary]

It's 20 (or so) light years from Earth.

To put that in a context that ordinary nerds without astronomy backgrounds can understand, it's 37,842,113,600,000,000,000,000,000 beard seconds from Earth.

Re:Astronomy

[Chabo]

From his third paragraph:

All of the planets imaged so far are relatively close, on a galactic scale. A few 10's of light years.

So, yes.

Re:Astronomy

[Kjella]

I always hear about these sorts of discoveries, of new planets more and more similar to earth, but having almost no astronomy background, I have no idea how significant they are.

Consider it a bit like breaking a world record, "closest to Earth" is a big title but ultimately you only need to beat the old record by an inch. The answer I'd say is "much, much closer than anything we've observed in the history of mankind and still very, very far away". There's so many variables you could tweak about size, distance from star, temperature, rotation time, composition, magnetic field, atmosphere, jupiter-type asteroid shields and whatnot. We're very far from saying whether anything we find is earth's twin or earth's distant halfcousin. Still, science is progressing at a wild pace, when I was a kid exoplanets was mere conjencture, something scientists had speculated about but never observed. The real joker in the equation is life, because well we know life exists on earth so without considering other exotic forms of life, our kind of life could exist on other earth-like planets. Or even just the realization that if we could get humans from this planet to that earth-like planet, we really could thrive on another planet, not just a bomb shelter on Mars - that'd be huge. We're getting closer and closer to that, but how exciting the steps are depends on your perspective.

Re:Astronomy

[arminw]

...How close are these planets, really, to earth?...

In order to have intelligent life, not only must the planet itself be similar to Earth in all respects, but the star it orbits must be very similar to our Sun. In this case, the star is too cold to emit the proper spectrum of light to use for knitting together atoms of carbon, hydrogen and oxygen, such as occurs here on Earth by the process of photosynthesis in green plants. This means that this star and others like it can be safely scratched from a list of planets may have intelligent life.

Re:Astronomy

[confused one]

We're talking about astronomy here... Average distance between stars is 3-4 light years. 10's of light years is rock-throwing distance. (as in: I bet I can throw a rock and hit it, from here).

Re:Astronomy

[Tubal-Cain]

We still have what, ten years left to invent an FTL drive and get there to preemptively apologize for reality television, right?

Faster than light merely means... Faster than light. c + 1 cm/second would count, but would get us there mere microseconds before the announcement that we had started the trip. Leaving now, we would need to go at >2c.

Re:Astronomy

[Anonymous Coward]

Pissed off? Well, Kevin Costner can just stay there. He hasn't done squat since "Field of Dreams" anyway.

Re:Astronomy

[Anonymous Coward]

It's 20 (or so) light years from Earth.

To put that in a context that ordinary nerds without astronomy backgrounds can understand, it's 37,842,113,600,000,000,000,000,000 beard seconds from Earth.

That may work for physicists, but for ordinary nerds and Europeans you should clarify that it's 194 petameters away.

Re:Astronomy

[holmstar]

Except it wouldn't be a direct path, rather a curve, and we would have to aim for where it really is, instead of where it was 20 years ago.

Re:Astronomy

[Anonymous Coward]

"There's more than enough information out there to explain how far that is from a human perspective."

Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.

If you don't believe me, you can always try a perspective vortex.

Re:Astronomy

[sycodon]

Substitute 150,000mph for 36,000.
http://www.aerospaceweb.org/question/performance/q0023.shtml

Re:Astronomy

[Hurricane78]

But only bearded "terrorists" and Stallman-lookalikes use that unit!
Which one are you?? Hmmm...?

Re:Astronomy

[w0mprat]

In order to have intelligent life, not only must the planet itself be similar to Earth in all respects, but the star it orbits must be very similar to our Sun.

No. We don't know that. We can't even begin to assign odds on what we might find when we turn over a rock on the surface of another world. With our sample size of 1, Earth, we have next to no data to support much to do with extraterrestrial life let alone any basis to declare where intelligent life can and cannot exist.

Oceans under Europa and other such worlds may harbor life, and the possibility of complex life is valid, therefore the possibility of intelligent (at some level) life can't be discounted.

Re:Astronomy

[jez9999]

If we can see planets a vast distance away so well, why are we having to send New Horizons all the way to Pluto to get a good piccie of it? Can't we point Kepler at it or something?

Re:Astronomy

[syousef]

If we can see planets a vast distance away so well, why are we having to send New Horizons all the way to Pluto to get a good piccie of it? Can't we point Kepler at it or something?

Even our best pics of Pluto with Hubble are large pixel garbage. NOTHING beats getting up close if you have the means to do it. Not just for imaging but also for aiming scientific instruments at the object. That's why we've had Pioneer, Voyager, Galileo, Cassini etc.

A good analogy would be getting a good but distant view of the local sports stadium from a sky scraper and me suggesting "Why do you need to pay for tickets to that event when you can see it from here with this telescope?". You just aren't going to get the same detail and information.

Re:Astronomy

[confused one]

As Syousef already pointed out, nothing beats an up-close look. Hubble only sees Pluto as a smudge across a couple of pixels. It's so small and so far away, it reflects very little light.

More to the point, however, is that Kepler is the wrong instrument for the job. Kepler can not "zoom" in on Pluto or any other planet. Kepler isn't designed to do that. It is designed to monitor the stars in a patch of sky, (about 100,000 stars in all) and watch for subtle variations in intensity. It can not "see" the planets but should give us an estimate of how many we can expect to find in the future as well as give us a few specific targets to concentrate our efforts on. I believe the expectation is Kepler may find a few hundred planets within it's 2-3 year life expectancy. Wikipedia has a reasonably good description of it.

Hubble and Keck(?) have managed to capture a couple of images of planets around nearby stars like Gliese 581. It's only been possible because the stars in question are fairly dim, the planets are really big and/or really close so they reflect a LOT of light (relatively speaking). It helped that in once case it was a planetary nebula with a convenient gap in the disk, kind of like the gaps in Saturn's rings. Basically a great big sign that read "LOOK HERE".

In the not to distant future, there's a mission planned that's euphamistically called the Terrestrial Planet Finder. It's currently on hold, a project with no funding. This should be able to image Earth sized planets in the habitable zone around nearby stars. Please keep in mind that when I say "image" I mean a discernable handful of pixels, enough to get a spectrograph from. It's be nice just to positively know it's there, and know what the atmosphere's main chemical components are.

Re:Astronomy

[Anonymous Coward]

Why not just broadcast a post-content apology to them?

Hey, wait a minute! Screw apologising to aliens, why aren't they apologising to ME?

Re:Astronomy

[arminw]

.....With our sample size of 1, Earth.....

This has more to do with the laws of physics and chemistry. As far as we can tell, these apply equally throughout the known universe. Physical life based on carbon is the only one capable of forming the complexity and versatility needed for even a single cell organisms to exist. The atomic binding energies of carbon, hydrogen and oxygen have to be matched to the spectral photon energies for a process such as photosynthesis. The spectrum of our star, the Sun, is remarkably well matched to the atomic and molecular properties of these elements.

There are many factors that must be matched in order to achieve the conditions needed for life. For example, any two or more stars must not be closer to each other than about 3.8 light years, otherwise they would influence the long-term orbits of any possible life harboring planet to fall outside of the habitable zone at times. This one single factor alone eliminates about half of all known stars as being host to a planet similar to ours. Our closest stellar neighbor, Alpha Centauri, it is about 4.2 ly from here.

Re:Astronomy

[Lars T.]

Because we want a picture, not just a (few) pixels.

Re:Astronomy

[some guy I know]

Except it wouldn't be a direct path, rather a curve, and we would have to aim for where it really is, instead of where it was 20 years ago.

Actually, you have to aim to where it will be when it gets there, not where it is now.

Actually actually, you have to take gravity, stellar wind, etc., into account, so you have to aim in some direction so that it will be where it will be when it gets there.

And then you have to make course corrections to avoid comets, asteroids, V'ger, Klingon battle cruisers, and so forth.
Rocket science is hard.

Re:Astronomy

[Anonymous Coward]

separate it's image
how close it's orbit
it's estimated mass

"its".

A few 10's of light years

"10s", or, better, "tens".

just say, that based on

"just say that, based on".

look. (although

"look (although" or "look, although".

If choosing "look (although" above, then
tried hard enough.

"tried hard enough).".

do a fly by

"fly-by".

Re:Astronomy

[Anonymous Coward]

within it's 2-3 year life

"its".

not to distant

"too".

It's be nice just to

"It'd".

but what about Earth 2...

[squoozer]

This is very interesting but no where near as exciting as finding another Earth like planet. I suppose we will have to wait for the next generation of telescopes before we find it though.

What is a little surprising though is how many planetary systems we have found that are very different to our own. I can't believe ours is unique but perhaps it's quite rare.

Re:but what about Earth 2...

[Chris Burke]

This is very interesting but no where near as exciting as finding another Earth like planet. I suppose we will have to wait for the next generation of telescopes before we find it though.

Well the 'e' planet is somewhat earth-like in mass and possibly earth-like in composition. It's not in the habitable zone for the star, but the closer a planet is to the star the easier it is to detect, and this exoplanet is at the very edge of our ability to detect (thus why this is news -- smallest exoplanet ever found). So you're right, we'll have to wait for technology to advance to find earth-sized rocky planets in the habitable zone (especially of non-dwarf stars).

What is a little surprising though is how many planetary systems we have found that are very different to our own. I can't believe ours is unique but perhaps it's quite rare.

I'm not sure anything we've found suggests that our type of solar system is rare. The limitations of our detection method by and large assures we'd find systems different from our own first. Astrophysicists might not have expected to find gas giants very close in to stars, but if they exist, we were going to find those first. The two main things that seem to have changed to me are that 1) we've gone from having nothing but our own solar system as an example and thus assuming ours was the model for all of them, to have many more examples showing different types and 2) we've learned that solar systems seem to be pretty common.

If we get to the point where detecting a solar system like ours would be simple, and despite finding thousands of others we don't find any like ours, then maybe that points to rarity. Right now though I doubt we're anywhere near being able to say that.

Re:but what about Earth 2...

[0xdeadbeef]

One in a thousand still means the galaxy has millions of earth-like worlds. "Rare" is relative.

Re:but what about Earth 2...

[Kell Bengal]

Maybe our type of planet is just difficult to find because it's so (relatively) small?

Re:but what about Earth 2...

[flaming error]

> This is very interesting but no where near as exciting as finding another Earth like planet.
Planet Gliese 581 e is an earth-like planet. It's just not in an earth-like orbit.

Re:but what about Earth 2...

[camperdave]

It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.

Re:but what about Earth 2...

[DragonWriter]

I'm not sure anything we've found suggests that our type of solar system is rare. The limitations of our detection method by and large assures we'd find systems different from our own first. Astrophysicists might not have expected to find gas giants very close in to stars, but if they exist, we were going to find those first.

To elaborate on that (you covered the distance part, yourself), the main factors is detecting exoplanets right now are (1) its easier to detect bigger exoplanets, and (2) its easier to detect exoplanets closer to the stars they orbit. So, gas giants orbitting close to the stars are comparatively easy to detect, anything smaller and/or more distant is harder.

You can't generalize well from the results of a highly-biased detection system.

Re:but what about Earth 2...

[nautsch]

Whoa, that was wrong.

1. There is not an infinite amount of space
2. since when is infinity - x = something finite?

Re:but what about Earth 2...

[zacronos]

There's something I wonder about which sounds like it would be enlightening to GP as well:

If we were using our current detection technology to examine a solar system that has a planet exactly like earth, orbiting a star exactly like our sun, with the same orbital period, etc... how close would the solar system need to be for us to recognize those features? Could we recognize an earth-sized planet orbiting a star in the habitable zone if it were 20 light-years away? What about 30 light-years? How close would we need to be in order to recognize that it is covered in liquid H2O oceans? Would the presence of other larger and/or more-closely-orbiting planets (such as Jupiter, Saturday, Mercury, Venus, etc) make that even more difficult?

Anyone have any insight into this?

Re:but what about Earth 2...

[daemonburrito]

Whoa, that was wrong.

Yes, but...

In many of the more relaxed civilizations on the Outer Eastern Rim of the Galaxy, the Hitch Hiker's Guide has already supplanted the great Encyclopedia Galactica as the standard repository of all knowledge and wisdom, for though it has many omissions and contains much that is apocryphal, or at least wildly inaccurate, it scores over the older, more pedestrian work in two important respects. First, it is slightly cheaper; and secondly it has the words Don't Panic inscribed in large friendly letters on its cover.

Re:but what about Earth 2...

[Chris Burke]

Oh wow, you mean the population of the universe isn't really zero?

Give this man a Nobel Prize!

Re:but what about Earth 2...

[dontmakemethink]

I can't believe ours is unique but perhaps it's quite rare.

Every star and planet is unique. They weren't made from an assembly line y'know!

And don't forget our form of life is equally unique, so it's a real needle-in-the-haystack situation. Kepler can search 10 x 10 degrees at a time, but with limited depth per scan, i.e. it has to change focus for objects 80 light-years away compared to objects 20 light-years away.

Then there's the inconvenient fact that communications take so long between such distant objects. Gliese 581 is 20.5 ly away, relatively nearby, but we could not expect a response to any message sent for 41 years, nor could any inhabitants of Gliese 581. The images taken are as it appeared when Bobby McFerrin's Don't Worry, Be Happy topped the charts.

Re:but what about Earth 2...

[vishbar]

Hand in your geek card. Read The Hitchhiker's Guide to the Galaxy. See the doorman for reissuance.

Re:but what about Earth 2...

[bsane]

Second that great question... anyone, have an answer?

Re:but what about Earth 2...

[Anonymous Coward]

Wow - that has so many errors it's unbelievable. It's the exact opposite of informative.

Space is not necessarily infinite. In fact, everything I've heard about it indicates it is quite finite (imagine being a 2d object on the top of a 3d sphere).

Even if it was infinite, you could apply your "logic" to show that the number of planets is actually finite - space is infinite, but not every portion of space is a planet, therefore there are a finite number of planets.

This is the best link I could fine. Essentially, if there are an infinite number of planets, the subset of inhabitable planets need not be finite.

Simple proof - consider the set of planets . Assume it is infinite. Apply some kind of ordering on the set. Mark every other planet non-inhabitable. Thus you've clearly got an infinite number of inhabitable & uninhabitable planets.

Also, you've the number of inhabitable & uninhabitable planets is the same, thus your probability is equal in finding an inhabitable planet.

You can also have it favourable to find inhabitable planets. Consider the sets except make every 10th planet uninhabitable.

Your specious logic only continues. In fact, it only gets more wrong. If you only have 1 inhabitable planet in the universe, then it is expected that you find other people from time to time since they can't be anywhere else in the universe.

Re:but what about Earth 2...

[Anonymous Coward]

Holy fuck go back to your high school math class.

Re:but what about Earth 2...

[Anonymous Coward]

Well, it's certainly looking that way: rare.

As a kid I was raised with all sorts of talk about how many trillions of other planets there must be- it's all so big! Yet no one told me until recently that 90% of what's out there isn't even a planet; it's gas...dust...clouds.

I didn't realize that the position of Jupiter/Saturn as well as the Moon was a key part in shielding this one from impacts.

As it turns out, this is a surprisingly rare planet, indeed.

Re:but what about Earth 2...

[emjay88]

see #27678705 above.

Re:but what about Earth 2...

[Metasquares]

There's someone named Zeno with whom I think you'd get along...

Re:but what about Earth 2...

[Anonymous Coward]

[HHG2G quote snipped]

Funny stuff...and logical at face value.

Rest in peace, Douglas Noel Adams....

Re:but what about Earth 2...

[Alsee]

According to the article the gravity of this new planet causes about a 7 km/hour wobble in it's parent star, and that is right about at the current limit of out ability to detect.

Here's my back-of-the-envelope calculations if you were trying to detect the earth:
This planet is 1.9 times the mass of the earth, so the earth would cause 1.9 times smaller wobble in the sun.
Our sun is about three times heavier than this dwarf star, so the sun's wobble would be about 3 times smaller.
The earth is about 13.7 times further from the sun, so the sun's wobble would be about 13.7 squared = 187.7 times smaller.

If I did that right... it means trying to detect the earth around the sun would mean trying to see a 1,070 times smaller wobble. And we were barely able to detect this planet.

This star is 20.3 light years away. The nearest star is 4.3 light years away. Even at the nearest star, we aren't even close to being able to detect the earth(*). The only reason we could detect this planet is because it was so close to it's parent star. The fact that this planet is bigger than earth and the parent star is a dwarf helped, but it's mostly about orbital distance. This planet is so close to its star that the planet's 'year' is about 75 hours long. The planet wobbles it's parent star by 7 km/hour every 75 hours. That's what we spotted. The earth wobbles our sun by about 0.007 km/h every year.

(*) Actually detecting the earth would be extremely easy because of all the radio signals we broadcast, but aside from that, no.

-

Planets and moons

[nizo]

Gliese 581 d is probably too massive to be made only of rocky material...

Even if it isn't habitable, it might still be large enough to have a habitable moon perhaps?

Re:Planets and moons

[American Terrorist]

Only if you eradicate the ewoks first. God those things are annoying. But hopefully tasty.

Re:Planets and moons

[Robotbeat]

One interesting thing about Gliese 581 d not being made of rock is that it might have almost the same surface gravity as Earth:

Volume of a sphere=(4/3)*pi*radius^3
radius of sphere=((.75/pi)*volume)^(1/3)
volume=mass/density
radius=((.75/pi)*mass/density)^(1/3)
mass=7.5*mass of earth
density=2kg/liter (twice that of water)

acceleration due to gravity=Gravitational constant*Mass of planet/(radius)^2

thus, plug this into google=
(Gravitational constant)*(7.5*mass of the earth)/((7.5*mass of the earth)/(2kg/liter)*.75/pi)^(2/3)

google gives us: 9.7764354 m / s^2

Yay!
Now, we just need a breathable atmosphere! And light-speed spaceships (or faster)!

Re:Planets and moons

[Anonymous Coward]

Nah, it's too close to its star to be habitable.

Re:Planets and moons

[Anonymous Coward]

That's no moon...

Re:Planets and moons

[Anonymous Coward]

Only if you eradicate the ewoks first. God those things are annoying. But hopefully tasty.

Fortunately, the Massassi were already eradicated.

Re:Planets and moons

[lazyforker]

Gliese 581 d is probably too massive to be made only of rocky material...

Even if it isn't habitable, it might still be large enough to have a habitable moon perhaps?

That's no moon.

Re:Planets and moons

[Anonymous Coward]

Only if you eradicate the ewoks first. God those things are annoying. But hopefully tasty.

For some reason, I imagine them tasting like cat.

Re:Planets and moons

[Chabo]

I hope many Bothans died to bring us this information.

Re:Planets and moons

[fiannaFailMan]

Only if you eradicate the ewoks first. God those things are annoying. But hopefully tasty.

I'm pretty sure they became extinct after the debris from the Death Star fell on the Sanctuary Moon.

Re:Planets and moons

[Samah]

Even if it isn't habitable, it might still be large enough to have a habitable moon perhaps?

That's no moon...

Re:Planets and moons

[Alsee]

Uhmmmmmm..... neat calculation, but where did you get the assumption that this planet was a big blob of water?

-

Good news

[KingPin27]

"could even be covered by a large and deep ocean â" it is the first serious "water world" candidate" .. Good.. I wonder if we can export Kevin Costner.

Re:Good news

[Anonymous Coward]

The best evidence of a âoewater worldâ would be the discovery of Smeat!

Re:Good news

[Anonymous Coward]

I just thought it funny that it said " it is the first serious "water world" candidate," by someone named UDRY! Sorry but it gave me a laugh

Re:Good news

[BotnetZombie]

Well, since you're asking, Python has this functionality now:

import antigravity
export("Kevin Costner", "Gliese 581 d")

Apologies to xkcd

Re:Good news

[JJJK]

It's probably already inhabited by Kevin Costners. Or at least Kevin Costner-like creatures.

Call me when we find an auric world.

[Chris Burke]

Water worlds always have the crappiest minerals. Oh look more alkalines. Yay. It won't be worth spending the fuel to land on Gliese 581 d, much less the cargo hold space. Gliese 581 e might have iron and other metals, but being so close to the star it probably has major hot spots. So that's probably not worth landing on either until we meet the Melnorme and buy some tech off them.

Oh well. Eliminating planets to explore is good too. There's a lot of stars in the sky, you know, and only so much time to explore them before the UrQuan return.

Re:Call me when we find an auric world.

[Kell Bengal]

We should check out Vega. Maybe we'll find something interesting.

Re:Call me when we find an auric world.

[Arthur Grumbine]

My galactic kingdom for a mod point!

Re:Call me when we find an auric world.

[Quothz]

We should check out Vega.

No. What happens on Vega, stays on Vega.

Re:Call me when we find an auric world.

[Rob Bos]

I hear Beta Pegasi I is worth a trip.

Re:Call me when we find an auric world.

[Anonymous Coward]

No. What happens on Vega, stays on Vega.

That's what you said about Uranus and we all know how that turned out.

Re:Call me when we find an auric world.

[DNS-and-BIND]

Oh, God, I was SO ready to get rid of those incessant attacks. Save me.

Re:Call me when we find an auric world.

[vrmlguy]

Gliese 581 e might have iron and other metals, but being so close to the star it probably has major hot spots.

Major hot spots? The place will be swarming with college students on spring break before you know it.

Re:Call me when we find an auric world.

[Anonymous Coward]

Just as long as we never have to go back to Alpha Cerenkov I again. I fear for the safety of my hunam orifices.

Re:Call me when we find an auric world.

[Chris Burke]

Major hot spots? The place will be swarming with college students on spring break before you know it.

Huh, maybe we can then collect them for the organic information we need to trade with the Melnorme! This could work!

Re:Call me when we find an auric world.

[Grishnakh]

No, there's probably just a bunch of Vegans there.

Let's blow this popsicle stand

[benwiggy]

Only 20 years away? So, by the time global warming gets catastrophic, we can already seed another world.

Meh.

As in Moonraker, we send the sexy geniuses first, right? Or do we send the Telephone Sanitizers and hairdressers, like in HHGG?

Re:Let's blow this popsicle stand

[Conspiracy_Of_Doves]

Yeah, if we were able to travel at the speed of light.

Re:Let's blow this popsicle stand

[Anonymous Coward]

You thinking about a career in hairdressing or telephone sanitation?

Re:Let's blow this popsicle stand

[Chris Burke]

As in Moonraker, we send the sexy geniuses first, right? Or do we send the Telephone Sanitizers and hairdressers, like in HHGG?

Well according to the travel register, you're booked on the first flight! Take that however you want.

Re:Let's blow this popsicle stand

[A. B3ttik]

By who's observation?

Don't the actual passengers get there in a few hours, their own time, or something crazy like that?

Re:Let's blow this popsicle stand

[nizo]

By someone standing on either Earth or the destination planet? Though it just occurred to me, I find it cool that to the photons from my lcd monitors I am traveling towards them at the speed of light.

Re:Let's blow this popsicle stand

[Anonymous Coward]

No it shouldn't read that way. A light-year is a valid unit of measurement, which is derived from the distance one travels in a year at the speed of light. But that doesn't make "light-year" an invalid derived measurement.

Re:Let's blow this popsicle stand

[steelfood]

It's actually a cookbook.

Re:Let's blow this popsicle stand

[icebrain]

Who the hell modded this insightful? While parent seems to have an understanding of what it means, the light-year is an internationally-accepted unit of length. Everybody knows what it means. His pedantic rephrasing of it is redundant, if that...

Re:Let's blow this popsicle stand

[DragonWriter]

Who the hell modded this insightful? While parent seems to have an understanding of what it means, the light-year is an internationally-accepted unit of length. Everybody knows what it means. His pedantic rephrasing of it is redundant, if that...

The post it was responding to clearly interpreted "20 light-years" as 20 years travel time, so GP's explanation that it was 20 years if and only if travelling at the speed of light, something we are notably incapable of doing at the current time, was, taken in context, neither "pedantic" nor "redundant", but perfectly appropriate and relevant.

Re:Let's blow this popsicle stand

[Smelly Jeffrey]

Thank you.

Re:Let's blow this popsicle stand

[maxume]

With current technology, speeding up and slowing down would each take at least months. If you managed to get up to 0.5 c, the trip (for the passengers) would take more than 34 years. If you got up to 0.9 c, the trip would take more than 9 years.

Very close to c, the trip would be nearly instantaneous (for the passengers).

(I assumed that gravity equivalent acceleration would be quite a feat, and used the table here:

http://www.fourmilab.ch/cship/timedial.html

)

Re:Let's blow this popsicle stand

[Anonymous Coward]

The GP used the phrase "20 years away" which is a common misunderstanding of the phrase "20.5 light-years away." Your objection to Smelly's explanation only makes sense if you're ingnoring the original misunderstanding.

I encourage people to avoid this by using the metric system. The star is 194 petameters away.

Re:Let's blow this popsicle stand

[KC7JHO]

Ouch, I think I just got one in my eye!

Re:Let's blow this popsicle stand

[icebrain]

Ah, I see it now. I read your post as saying

The phrase "20.5 light-years away" should read "20.5 years away, traveling at the speed of light."

I missed the "be". My apologies; it's not been a good day.

Re:Let's blow this popsicle stand

[Kagura]

Iambic, too.

Strange biology

[allaunjsilverfox2]

Since actual detection of a planetary spectrum is yet to be achieved, it's all still guess work. But it would be fun to imagine what kind of compromises biology would have to make in high gravity planets, that is if they made it beyond single cell organism stage. Even then, life would to have to find a way to deal with the increased amount of elements on a super earth.

Re:Strange biology

[SpitfireSMS]

Thats what makes me wonder why we are considering this dwarf star a candidate in the first place.
Why wouldnt we start with stars that are most similar to our sun.

Doesnt the white dwarf occur after the supernova explosion? Or something like that? Im no astronomer.

Wouldnt that mean that it EXPLODED and ENGULFED an area much larger than its current size, potentially destroying all life that could have been on these planets anyway?

Re:Strange biology

[confused one]

It's a red dwarf, not a white dwarf. Red dwarfs could be thought of as small low-energy stars. They're more numerous and last longer than Sun-like stars. It's a gimme -- because it's nearby, less massive, and produces less light, it's easier to see stuff around it.

Re:Strange biology

[ijakings]

The Dave Lister count is also much Higher for Red Dwarves.

Did any one else read that as...

[Saint Stephen]

Did anyone else glance at Gliese and read that as uncomfortably close to Goatse.cx?

By the way, off topic, as it is, how does one prevent from being fooled by tinyurl links to goatse.cx?

Re:Did any one else read that as...

[xmason]

Embiggen:

http://ghill.customer.netspace.net.au/embiggen/

Re:Did any one else read that as...

[4D6963]

On the tinyurl site you can choose to have a preview page that shows you the actual url when you click on one of their link (storing the preference as a cookie iirc).

Re:Did any one else read that as...

[4D6963]

Or you can use this extension https://addons.mozilla.org/en-US/firefox/addon/9549

Wanna see more: Celestia

[SalaSSin]

If you would like to know more, download Celestia, an open source project to cruise around the universe in 3D.
Just select "go to object" and type in "gliese 581", you'll get the orbits of the different planets already found too.

The neat thing is, you can just "cruise" around, speed up time to see how stellar objects move, and so on... Quite cool :-)

Re:Wanna see more: Celestia

[SalaSSin]

Oh, and btw: our sun is about 20 light years away from Gliese 581d. (Also found in Celestia)

Re:Wanna see more: Celestia

[SalaSSin]

Ok, just seen that someone posted the same while i was typing my stuff... Mod me redundant :-)

Re:Wanna see more: Celestia

[Anonymous Coward]

download Celestia, an open source project to cruise around the universe in 3D.
Just select "go to object" and type in "gliese 581", you'll get the orbits of the different planets already found too.

So THAT's how it's done! Amazing...

An exoplanet?

[Anonymous Coward]

An Exoplanet? Send in the Exosquad!

Extraterrestial life

[modrzej]

To state banally, once again it appears that Earth isn't the center of the Universe, or even an extraordinary spot. Sadly, mankind won't be ever capable of communicating with such a distant places. However, speculation about extraterrestrial life isn't pointless. In range of our capabilities and, moreover, not forbidden by limiting condition on light speed, is a spectroscopic measurement of atmospheres belonging to planets beyond the solar system. Thus, in principle probable, it would be a great achievement to find traces of organic matter.

Re:Extraterrestial life

[furby076]

To state banally, once again it appears that Earth isn't the center of the Universe, or even an extraordinary spot. Sadly, mankind won't be ever capable of communicating with such a distant places. However, speculation about extraterrestrial life isn't pointless. In range of our capabilities and, moreover, not forbidden by limiting condition on light speed, is a spectroscopic measurement of atmospheres belonging to planets beyond the solar system. Thus, in principle probable, it would be a great achievement to find traces of organic matter.

Those are some bold statements: 1) Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.
2) Not ever be able to communicate with distant places? You don't know what we will invent in the future. It may come out tomorrow, or it may come out in 300 years - but to say "never".
3) Speculation about other life is not pointless - it feeds our soul and imagination to wonder if there is something else. If humans thought exploring was pointless we would still be living in Africa, definitely never have crossed the ocean, let alone landed on the moon (something that people, 100 years ago, thought was impossible)

Finding organic material will be hard short of landing on the surface. We couldn't even do searches of Mars without sending a robotic device there, and even then it may miss something. It's hard, and may not get done in our lifetime (thought it might) but it is certainly not pointless or impossible, and considering how rare life is we should consider ourselves (and our planet) to be very rare and special, though hopefully not unique.

Re:Extraterrestial life

[SpitfireSMS]

Finding organic living matter on other planets would be fantastic, but unfortunately that wont be the first kind of extra-terrestrial life we find (prospective there is any).
Our most advanced instruments are just now able to detect exoplanets, and soon enough they may be able to actually scan the surface for signs of life.

If we COULD send instruments there that could detect microscopic living organisms, we might actually have a lot better luck at finding life.
This just isnt feasible currently, and were going to have to stick with superficial surface scanning for creatures crawling around until we can actually send instruments there that could report back.

If we did find intelligent life, I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it. Imagine being on Earth 200 years ago and finding something similar, with videos of aliens and things.
It would have been revolutionary, and eventually we may be able to greet another intelligent race in a similar fashion.

Oh the possibilities..

Re:Extraterrestial life

[Dyinobal]

You've got a pretty bleak outlook there. I don't actually have much faith in anything,but the one thing I do have faith in is the achievements that mankind is capable of.

Re:Extraterrestial life

[Samrobb]

Sadly, mankind won't be ever capable of communicating with such a distant places.

Did you even bother to read the summary? The star is about 20 light years away. That's a 20-year round trip for radio communications, sure... but we are currently capable of communicating with "such a distant places" (sic). We have been for the better part of a half a century.

Re:Extraterrestial life

[Domint]

1) Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.

The only reason we are able to detect life on Earth is due to proximity - so you're just as guilty of jumping to conclusions as the GP. We've found planets that differ wildly from Earth because the easiest planets to detect are the fuck-all-huge ones. Just because we haven't observed Earth-like planets yet does not mean they aren't all over the bloody place. They're just rather hard to spot with current technologies.

Re:Extraterrestial life

[modrzej]

"Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary." I was talking rather about size and material a planet is made of. With respect to this, it seems that there could be many earth-type objects. Is life on Earth extraordinary? Couldn't say that basing on scientific data. This question is not well-posed because theres no data yet. "Not ever be able to communicate with distant places? You don't know what we will invent in the future." Majority of planets we already discovered orbit stars so distant that it's not possible to actively communicate (two partners to form dialogue) because of the limit imposed by theory of relativity on light speed.

Re:Extraterrestial life

[nizo]

I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it.

Yeah, because if a big thing from another planet lands and I look inside and see a big red button attached to some unknown device, I'm gonna just press that puppy right away :-)

Re:Extraterrestial life

[mangu]

Finding organic material will be hard short of landing on the surface

If we do an absorption spectrum reading of the atmosphere, which can be done at astronomical distances, and find free oxygen that would be a strong evidence for life on that planet. Oxygen is so reactive that it wouldn't exist very long in a planet's atmosphere before combining with something, unless here is a process like life to replenish it.

Re:Extraterrestial life

[shma]

Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.

You are wrong about this. From the hundreds of planets we have found, we can easily extrapolate that there are many, many more planets (and many more rocky planets, as well) in the solar system than we have thought (maybe even 1 per star!). That makes the fact that we haven't found life yet on the planets we've searched for irrelevant. If there are a billion planets out there, we have to search a lot more before we can say definitively that life is rare in the galaxy.

Re:Extraterrestial life

[palindrome]

The star is about 20 light years away. That's a 20-year round trip for radio communications,

40 years round trip. That's a long time to wait for a response. Imagine we sent out a message announcing our presence and saying hello:

"Hello? This is humanity, we are [blah, blah - lots of info about us and Earth]..." ..... .....

40 years later and you get the response:

"Hi!"

How pissed would you be?

Re:Extraterrestial life

[Obfuscant]

If we did find intelligent life, I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it.

One of the fascinating free books I've been able to find for my Sony ereader was a short story "Test Rocket", I think it was called. We sent up a rocket with a mouse as a test. It disappeared. Several years later, an copy of the rocket came back, made out of materials "not of this planet" and three times the size of the original, containing what appeared to be a human.

Except he couldn't speak or communicate.

(In case the meaning was lost in summarizing, THEY are much bigger than we are and to them humans are just "laboratory mice".)

Re:Extraterrestial life

[MyLongNickName]

Actually, it would be much wiser to simply continue to talk for the whole twenty years than dialog like that. You would give the recipient a lot of information over that time, and hopefully they would reciprocate.

Re:Extraterrestial life

[kegger64]

That's a 20-year round trip for radio communications, sure... but we are currently capable of communicating with "such a distant places" (sic). We have been for the better part of a half a century.

Radio communication was invented in 1960?

Re:Extraterrestial life

[palindrome]

"Hello? This is humanity, we are [blah, blah - lots of info about us and Earth]..."

Was meant to signify that a lot of information would be sent.

I'm not sure that it would be "wiser" to talk for 20 years, though, mainly because that's plainly ridiculous. You wouldn't actually be doing some form of interstellar radio show you'd probably use binary to transmit information - 20 years worth of raw data would probably be excessive.

Re:Extraterrestial life

[phosphorylate this]

You wouldn't but I would, then I'd lick the casing. My dog might even widdle on the side of the probe or hump one of its legs.

I'm pretty sure one constant throughout the universe will be that life invariably leads to unbelievable stupidity.

Re:Extraterrestial life

[Anonymous Coward]

*Slams book shut*

Thanks. Thanks a lot.

*Stomps off to sulk*

Re:Extraterrestial life

[MyLongNickName]

Actually, the idea of talking continuously came from an Arthur Clark short story... have Googled but cannot come up with a title :(

Re:Extraterrestial life

[palindrome]

The problem you have though is that if the aliens are really polite they'll just sit there waiting for you to finish before they respond.

Re:Extraterrestial life

[ITJC68]

The kicker is that radio does not travel at the speed of light. Probably will take longer than 20 years. We should be using lasers emitting binary patterns or something. At least that way they should see something in 20 years. On and btw radio has been around since the 20's. Any of those broadcasts should have reached them by now and they are probably not interested or think we blew up after WWII.

Re:Extraterrestial life

[MyLongNickName]

The kicker is that radio does not travel at the speed of light

Where, pray tell, did you come up with this?

Re:Extraterrestial life

[palindrome]

I believe they do in a vacuum.

Re:Extraterrestial life

[Dragonslicer]

My guess would be the region of his ass. I'd love to know what he thinks radio is.

Re:Extraterrestial life

[vrmlguy]

Imagine we sent out a message announcing our presence and saying hello:

"Hello? This is humanity, we are [blah, blah - lots of info about us and Earth]..." ..... .....

40 years later and you get the response:

"Hi!"

How pissed would you be?

Not as pissed as I would be if the response was a message telling us how our civilization could grow larger, last longer, and bring more pleasure to our partners.

Re:Extraterrestial life

[Draek]

Are you sure it was from Arthur Clark? I once read a short story by Asimov on that, and after some Googling I found this.

Re:Extraterrestial life

[dtolman]

Where do you get that radio waves don't travel at the speed of light? They're photons. In a vacuum. They're going just as fast as your friggin lasers.

And don't get your hopes up about radio transmissions being picked up either. Take the biggest receiver on Earth (Arecibo - 1000 feet across), put it in space and how far can you go before you can't make out TV/radio transmissions? Pluto.

The carrier can go out farther - maybe a light year before Arecibo loses it. And radar beams even farther (assuming the beam sweeps over you). But all those say is that we're here. Not what we're saying.

Re:Extraterrestial life

[Rich0]

Agreed - lots of stuff could be detected spectroscopically on an Earth-like world.

Those kinds of technologies can't be applied to other planets in our own solar system. I mean, sure, technically we can do a spectrocopic study to rule out Mars being a jungle paradise, but I don't think that is really at issue.

We need probes for nearby planets since we already know they aren't teaming with life, but there is a question as to whether they are absolutely sterile.

Now, if a spectroscopic study of an exoplanet shows no sign of life that isn't proof positive that there isn't some microbe buried in a rock somewhere, but it would be a strong indicator that we're not going to find green men and other advanced organisms walking around on the surface.

Re:Extraterrestial life

[Anonymous Coward]

If we did find intelligent life, I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it.

Assuming the life uses sight and hearing as primary senses in the same part of each wavelength spectrum. And has manipulator digits and gets the idea of "push a button".

Probably what would happen would be Q'*zkv would come across it, be curious and squirt a few activation enzymes at it and get no response, accidentally bump into the button, scan in the infrared and ultrasonic, and then decide it's quite uninteresting.

Re:Extraterrestial life

[swillden]

I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it.

Yeah, because if a big thing from another planet lands and I look inside and see a big red button attached to some unknown device, I'm gonna just press that puppy right away :-)

Good point. Clearly the button should be green. Duh!

Re:Extraterrestial life

[MyLongNickName]

Thank you! My memory is bad.

And for the record it is Arthur C. Clarke which both of us spelled incorrectly.

Re:Extraterrestial life

[Chris Burke]

Don't touch that, you fool! That's the History Eraser button!

Re:Extraterrestial life

[FrameRotBlues]

I think a lot of people would freak the fuck out if we sent them a bunch of information in English and they sent their responses in English.

I'd expect that any response would sound like static or gibberish, and we might not be able to decode it for a long time. As cheesy as some parts of "Contact" were, that part was probably about right: We receive their "message" and then spend months going, "WTF did they send us?"

Re:Extraterrestial life

[Taibhsear]

'Pick me up'
Hmm... (grabs)
*POOF*

Re:Extraterrestial life

[Shard.Oglass666]

Well I for one, Do consider the humans of Earth to be SPECIAL. And I have to wonder why they aren't all wearing those 'special helmets' in order to chew gum and walk at the same time?...Or am I thinking of politicians?

Re:Extraterrestial life

[Grishnakh]

You're assuming that light speed is an absolute limit. Remember, 100 years ago, humans thought heavier-than-air travel was physically impossible. The idea that atoms could be divided or joined was also thought to be impossible.

Considering we've barely even taken a few steps off this rock, the idea that our current understanding of physics is complete is laughable.

Re:Extraterrestial life

[palindrome]

My rather clumsy joke seems to have become confused with an opinion.

You see, I was saying it would be quite annoying if you waited 40 years and all you got from an alien intelligence was a simple recognition of your message. It was an attempt at humour, and for that I express my humble apologies.

As a sign of penance I will respond to your "Insightful" comment in a serious manner, and jettison all humour.

Yes, it would be weird and freaky if we spoke to aliens in English and they responded in English. Insightful.

It would, in fact take a long time to decipher a message sent to us by an alien. Insightful.

Mod parent up! (insightful).

Re:Extraterrestial life

[modrzej]

From fundamental principles: 1) The principle of relativity, 2) Homogeneity of space and time one can derive that Galilean and Einsteinian (special relativity) theories are the only embodiments of the principle of relativity. (http://arxiv.org/abs/physics/0302045) But we know that Galilean transformation is gross approximation compared to special relativity. There's more truth in the latter. There must be this limit because of more fundamental laws.

Re:Extraterrestial life

[Anonymous Coward]

Almost right... but not exactly. Oxygen can pile up in massive quantities if all the material that can combine with oxygen has already done so.

I heard that ancient Venus might have had oxygen atmosphere, because H2O molecules were broken by ultraviolet light from the sun, and then the lighter H2 would escape.

A very strong indicate of life, as I heard, is oxygen *and* methane co-existing (just like the Earth: we have a small but very detectable amount of methane in our atmosphere), because they react with each other rather well.

Conclusion: you want to hide from alien probes detecting intelligent life (to destroy potential competitors)? Stop farting.

Re:Extraterrestial life

[LateArthurDent]

1) Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.

We've looked at one Earth-like planet. That's Earth. You need larger samples of earth-like planets (rocky, about the same size, in the habitable zone) with no life before you can say Earth is special at all.

And before you say that not finding any other Earth-like planets already makes Earth special, you need to remember that we don't have the technology to find them. They could be at single every star we've looked at, and we still wouldn't have seen them. Technology is improving though, and we're becoming able to find smaller planets.

2) Not ever be able to communicate with distant places? You don't know what we will invent in the future. It may come out tomorrow, or it may come out in 300 years - but to say "never".

Relativity made the entire concept very hard. I think it's more realistic to assume we'll never find a way around relativity than to assume that technology and knowledge will one day give us some magic. Sure, we might develop something and that'd be great, but we shouldn't count our chickens before our eggs are hatched. Hell in this case, we don't even have the eggs yet, there's no evidence of any phenomenon that bypasses the whole speed-of-light limit, time-dilation difficulties that can actually be used to transmit information.

3) Speculation about other life is not pointless

We agree completely there.

Finding organic material will be hard short of landing on the surface.

That's not true at all. Spectroscopy has been able to find organic material in several distant places, without having to land anything there. Just yesterday there was a story on slashdot about ethyl formate around Sagittarius B2

Re:Extraterrestial life

[syousef]

1) Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary

How many have we looked at. 7 or 8 other than Earth (depending on whether you agree with the latest IAU definition of Planet) here and we've seen nothing more than the WOBBLE from a few hundred more that aren't in the habitable zone? Do you have ANY concept of how many stars there are out there.

2) Not ever be able to communicate with distant places? You don't know what we will invent in the future. It may come out tomorrow, or it may come out in 300 years - but to say "never".

You do never know what'll will be discovered, but nothing we know of now even in theory can communicate faster than light. Would I stake my life on never? No, but I don't think it'll happen in my life time or that of anyone I know.

Re:Extraterrestial life

[FrameRotBlues]

No no, I got your joke in the first place, I just expanded on it without acknowledging it first. My bad.

But truly, in the grand scheme of things, 40 years to get a reply would be astounding, even if it was just a recognition that we sent a message. It would be kind of a bummer if that's all they sent was "We're here" without telling us ANYTHING else, but really, that little bit of recognition would go a long, long way, IMHO.

Re:That's nothing

[SalaSSin]

Yep: A whole lot less...

Re:threadjack

[Anonymous Coward]

confirmed. earthlink.net not loading.

Re:BOOOOOORING!

[American Terrorist]

Quit karma-whoring. This article is boring as shit and you know it.

This comment would be at least +4 Funny if you had just stopped there.

Everything except orbit and mass is speculation

[Morgaine]

The science of extra-solar planet detection is very interesting, but speculation about surface conditions that might exist doesn't reflect the science at all, it's just fodder for the media and bloggers.

The only things we know are extremely rough estimates of orbital parameters and mass, although the host star is well characterised. The speculation is conjuring up quite specific images in people's minds, and while fun, they're not justified. It's leading people without an astronomy background astray.

Re:Everything except orbit and mass is speculation

[0xdeadbeef]

"'The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the 'habitable zone' -- a region around the host star with the right conditions for water to be liquid on a planet's surface', says Michel Mayor from the Geneva Observatory, who led the European team to this stunning breakthrough."

Indeed. Who do these scientists think they are, making their work sound interesting?

We get it already!

[glwtta]

Ok, so they seem to have gotten pretty good at finding planets that are bigger than Earth - is it really necessary to announce every single one of them?

Re:We get it already!

[Anonymous Coward]

Yes! And sometimes, you'll get the same announcement more than once (in case you forgot).

SCIENCE!

What class?

[amliebsch]

So, is it an M-Class planet or not?

Re:What class?

[confused one]

No.

Re:What class?

[Captain Nitpick]

So, is it an M-Class planet or not?

The Star-Trek planet classifications are useless. They confuse too many independent variables into one label, and don't cover all the possible combinations. You can't even make Uranus and Neptune fit them. If we looked at an Earth from an alternate timeline where life never started, the planet would not fit into any of the Star Trek classes.

If you want, we can say that Gliese 581 e is too close to its star for liquid water to exist, and thus rules out Class M.

However, take Gliese 581 d. Unless it already has life to put oxygen in the atmosphere, d has no Star Trek planet class. But if the hypothesis that it is low density is right, and it possesses an atmosphere with a greenhouse effect, then it's waiting for us to waltz over and start terraforming.

Water World?

[thbigr]

Mesome thinks deasum new place for mesome live.

Oblig. That's no Exoplanet...

[JoshDM]

... it's a Beowulf Cluster.

What, you were maybe expecting something else?

Re:Oblig. That's no Exoplanet...

[Anonymous Coward]

No, no... that's really not obligatory. It's not even remotely funny. It's not an exoplanet, it's a beowulf cluter? Of what? It sounds like you've augmented the Chewbacca defence with the Chewbacca punchline. Ladies and gentlemen, this joke makes no sense. Why would Chewbacca, a Wookie, be talking about a beowulf cluster when referring to an exoplanet? That makes no sense! Ladies and gentlemen, I'm not making any sense. This makes no sense.

Better hurry!

[Anonymous Coward]

You do realise that the universe has an awkward tendency to expand, right?

So it's 20.5 lightyears away *now*...
We better get going quickly!

*packing bags*

Re:Better hurry!

[Chabo]

It would be really awkward if we sent a mission to that planet, only to find out that our speed of travel was less than the speed of expansion...

"Crap."

So they found my mother-in-law?

[DJCouchyCouch]

rah rah rah rah!

Luckily, my wife doesn't read slashdot.

Re:So they found my mother-in-law?

[maxume]

How often does she call you DJCouchyCouch?

Re:So they found my mother-in-law?

[Anonymous Coward]

You are going to be in so much trouble when my Mom hears about this, mister.

A habitable moon...

[Anonymous Coward]

Wait a minute... that's no moon... it's a^H^H^H^H

Bah you bastard! You set me up!

'lighest'?

[Anonymous Coward]

Wouldn't the correct term actually be 'least dense', since the word light implies weight, not density?

Re:'lighest'?

[MyLongNickName]

No. The correct term is lightest. The writers are not making any indication about density in the summary. They are indicating they they have indeed found the lightest planet discovered using these techniques. This planet wouldn't even be close to being the least dense planet ever discovered. Gas giants are typically far less dense.

(having to wait my obligatory five minutes between posts)

Re:'lighest'?

[MozeeToby]

Actually, wouldn't the correct term be 'least massive'? Heavy and light are measurements of weight generally and are pretty meaningless for objects that are in orbit. Unless it's considered kosher to use lightest/heaviest in this situation, sometimes I think English drifts faster than the average person can keep up with it.

Re:'lighest'?

[Alsee]

Actually the politically correct term would be 'least plus-size'.

-

compromises?

[mevets]

Maybe Life had to make compromises for low gravity planets, like earth, and finds it much easier to organize in high gravity planets with a lesser amount of elements (whatever the hell that means). Humility is a virtue.

Less than twice ?

[Anonymous Coward]

A vital question arises : does it have less than twice the problems of Earth ?

Rocky!?!!

[Anonymous Coward]

Screw That. Its Time to buy a Hummer and go Rock Crawlin! RAWR!

water world??

[Anonymous Coward]

I think it's kind of dumb to speculate (or even mention) that planet "d" could be a "water world". He's saying that only on the basis that the planet lies within the "habitable" zone where liquid water can exist. Ok, so liquid water can exist but there might not be any water at all. Or if there is, there could be continents sticking out of the ocean beneath the gaseous outer part of the planet.

Sayint that a planet that could be a "water world" because it orbits at the right distance for liquid water to exist is like saying "ohhh planet xyz is the same size as the Earth so it probably has land and oceans and air".

Water Worlds hmmph!

[Anonymous Coward]

Did anyone else notice that this report of a water world is by someone named "Udry"? Really, I rent trailers at U-Haul, but
a water-covered planet from U-Dry?

Re:Water Worlds hmmph!

[MyLongNickName]

Yeah, the AC who posted about 14 minutes before you noticed this as well.

Yeah

[elloGov]

In my pants

Re:Yeah

[Anonymous Coward]

That's what she said.

Innuendo

[limekiller4]

Soulskill writes:
"...it is the first serious "water world" candidate,' continued Udry."

Excellent.

Whiplash.

[solios]

The orbital period of these exoplanets make Mercury's 88 day loop seem positively sluggish by comparison. The rest of the planets in our system have much longer orbital periods - Earth's is a bit over four times mercury's - to say nothing of the geologic sloth of the outer planets.

That said, from what I know about gravitational microlensing (very little, admittedly), it makes sense that our existing telescopes are picking up a lot of "high speed" planets, and that it's going to take a long time (both in ramping up the tech and in tasking the scope to just sit there and stare at a star, waiting for something to blip by) for the "earth-sized rock in the habitable zone with an earth-length orbital period!" announcements to start rolling in.

That they're catching them smaller is fantastic. I look forward to the scopes catching 'em slower. :)

Re:Whiplash.

[Mendokusei]

it's going to take a long time (both in ramping up the tech and in tasking the scope to just sit there and stare at a star, waiting for something to blip by) for the "earth-sized rock in the habitable zone with an earth-length orbital period!" announcements to start rolling in.

I wouldn't think that an "earth-length" orbital period is all that important to determining if a planet can support life or not. Remember, the type of the star it orbits determines where and how large the habitable zone will be, so if we find a planet relatively the same size as Earth orbiting a star that is not as hot as our sun, the habitable zone for this planet will be much closer to the star in question; thus the orbital period could possibly be much different than our own, depending on exactly how close that planet must be in order to sustain liquid water. Likewise, if an earth sized planet is found orbiting a star that burns much hotter than our sun, the habitable zone would be much farther away from that particular star, again resulting in a different orbital period from our own.

Re:"famous system Gliese 581"?!?!? Huh?

[Anonymous Coward]

I guess that's a good sign. Because if such a benighted group of anencephalic twits can run one of the net's busiest sites, the world must be doing damn well.

It's a pretty busy site (in the top 1000), but at #942, I don't know if I'd call it "one of the net's busiest sites".

Pics

[VinB]

or it didn't happen.

Superluminal planets?

[T Murphy]

Planet Gliese 581 e orbits its host star -- located only 20.5 light-years away [...] in just 3.15 days.

The planet orbits a star 20.5ly away from it in just over 3 days? I figured if superluminal travel existed it would involve quarks or virtual particles, not entire planets! Not to mention I'm surprised that 20.5ly is apparently a small distance to orbit from ("only 20.5 light years away").

Paging Dr Einstein

[Gothmolly]

Given that they're 20 years away, IN THE MILLENIUM FALCON, is it even interesting if they are habitable or not? I can picture it now, we use a radio telescope to send "Hello" and wait 40 years to get back "A/S/L ?".

What?

[Anonymous Coward]

Ironic, a man named "U Dry?" talking about a water world...

In related news...

[GodfatherofSoul]

...the definition of "earth-sized" planet shrinks.

Here you go

[Anonymous Coward]

        .

Soon.

[w0mprat]

It is interesting the reason we aren't seeing more planets closer to earth size is simply the limits of the sensitivity of our observations. This is interesting, the star being red dwarf, such stars outnumber ones like our sun 10 to 1 in this galaxy, the Gilese system shows these stars could be very planet friendly.

Searching for investors

[OrangeTide]

I'm building an Ark and plan to retire to this paradise planet. The current crime rate is 0% and there are no taxes at all.
Invest now in this limited opportunity and don't be too late to take advantage of this exclusive offer.
Just reply to this thread with your bank routing number and account number along with the amount you wish to invest.

Is it really earth-like?

[long404]

According to this article Close-In Planets Mass Loss "gliese 581 e" might not at all be earth like planet but the core of a gas giant whose atmosphere was "eaten" by the star. What is left is probably a giant diamond. So pack your laser drills and lets go :)